1. Field of the Invention
The present invention relaters to a wet-processing apparatus and a wet-processing method for processing a substrate, such as a semiconductor wafer, by wet processes, such as a developing process, and a storage medium storing a computer program including a set of instructions for a computer to execute to carry out the wet-processing method.
2. Description of the Related Art
A resist pattern forming system for carrying out a semiconductor device fabricating process is built by connecting an exposure system to a coating and developing system. The coating and developing system has plural wet-processing units for processing a substrate by wet processes, such as a resist film forming process using a resist solution, an antireflection film forming process using an antireflection chemical solution and a developing process using a developer. The wet-processing units. Each of the wet-processing units is built by disposing a cup for preventing the scatter of a solution in a box, namely, an external case, disposing a spin chuck having a vacuum chucking function in the cup, and arranging a chemical solution spouting nozzle for spouting a chemical solution onto a substrate held on the spin chuck and a cleaning nozzle for cleaning the substrate with a cleaning liquid.
The coating and developing system has a thermal units for processing a substrate by a heating process and a cooling process before and after a substrate is processed by a wet process in the wet-processing unit, and transfer stages through which a substrate is transferred between plural carrying arms. These units and stages are called modules. Module numbers are assigned to the modules. A substrate carrying means is controlled to carry substrates according to a carrying schedule defining sequential order of the module numbers. A main arm provided with two or more carrying arms is disposed in each of processing stations in which the wet-processing units and the thermal units are disposed, respectively. The main arm receives a processed substrate from the processing unit and transfers a substrate to be processed to the processing unit according to the carrying schedule. Thus substrate replacement is performed for the processing units from the upstream toward the down stream processing units. The plural processing units are assigned to each of the processes and substrates are delivered sequentially to those processing units in increasing order of module numbers. Suppose that the coating and developing system is provided with, for example, six developing modules, substrates are carried sequentially to the six developing units in increasing order of the module numbers of the developing units.
In an invention disclosed in Patent document 1, plural wet-processing modules, for example, three wet-processing modules, use a single shared nozzle for pouring a chemical solution, and the shared nozzle is moved from one to another of the wet-processing modules to which a substrate has been delivered. Employment of the shared nozzle reduces the number of component parts, process conditions for the processing modules can be equalized, and reduces work for adjusting the shared nozzle because the single nozzle shared by the plural processing modules needs adjustment.
When intervals at which substrates are delivered to the processing modules are shortened, it sometimes occurs that a time for which each processing module needs to detain the shared nozzle is longer than those intervals. If substrates are carried sequentially to the processing modules according to the carrying schedule in such a state, it occurs that the shared nozzle is detained by the processing module holding the preceding substrate and the succeeding substrate is kept waiting in the processing module. Consequently, waiting time for which substrates are kept waiting increases cumulatively reducing the throughput of the system. Therefore, although the use of the single shared nozzle by the plural processing modules has various advantages, such a mode of use of the shared nozzle has difficulties in practical application.
Patent document 1” JP-A 5-267148 (Paragraphs 0021 and 0025, FIG. 5)